


My Underfell Headcanon

by Dragonsrule18



Series: The Tales OF Underfell Flowey And Frisk(Pacifist Route) [1]
Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell (Undertale), Angst, Backstory, Character Death, Character Study, Emotional Flowey (Undertale), F/F, F/M, Female Frisk (Undertale), Gen, Gender-Neutral Chara (Undertale), Good Chara (Undertale), Headcanon, Nice Flowey (Undertale), Nonbinary Chara (Undertale), Original Character(s), Pre-Undertale, Soft Chara, Spoilers - Undertale Pacifist Route, Underfell Flowey, Underfell Mettaton, Underfell Papyrus, Underfell Sans, Undertale Saves and Resets
Language: English
Status: Completed
Published: 2018-08-16
Updated: 2018-08-16
Packaged: 2019-06-28 10:45:06
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 1
Words: 4,885
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15705651
Author URL: https://archiveofourown.org/users/Dragonsrule18/pseuds/Dragonsrule18
Summary: These are my headcanons and backstories for my particular AU, The Adventures Of Underfell Flowey And Frisk, both the Neutral and Pacifist route series.  This contains my headcanon about why Asgore turned the Underground into Kill or Be Killed and why Flowey is good in Underfell as well as bios on the Fell characters and a look into Frisk and Chara's pasts before the Underground.More stories will be coming to these series soon!





	My Underfell Headcanon

**Author's Note:**

  * For [Rehlia](https://archiveofourown.org/users/Rehlia/gifts).



> This was inspired by the awesome Rehlia, who wrote a story with their own headcanons for the Underswap, Underfell, Swapfell, and Mobtale AUs and who gave me ideas for my own series. Be sure to check out their story Rehlia's AU Headcanon Corner! They have amazing takes on those AUs, and their other stories are awesome as well!

My Underfell Headcanon

**Backstory**

The moment this Underground turned from Undertale into Underfell happened when Asgore's parents were murdered by humans during the human-monster war. Asgore's grief turned into rage, and he vowed to take revenge on the humans. Under his orders, the monsters became much more violent against the humans, but still victory was not to be. The monsters were defeated and sealed Underground.

Asgore had not yet fallen as far as he would after Asriel would die, but he was determined to turn monsters into a fighting force. He trained the monsters under his command harshly to get them as strong as possible for when the barrier would eventually break. Only very rarely would he act like the gentle monster he had once been, and only around Toriel, who was pregnant with Asriel at the time monsters were sealed Underground.

When his son was born, a gentle kid with a kind spirit much like Asgore had been as a child, Asgore decided to train him hard and toughen him up, wanting his son to survive and be strong enough to handle anything. He was more like a sergeant than a father at most times, pushing Asriel to be a tough warrior and trying to eliminate any perceived weakness in his son. He was often harsh with him and rarely showed affection, which made Asriel feel unloved and like he could never get his father's approval. Wanting so much for his father to be proud of him, Asriel tried to hide his true kind nature and acted tough around everyone.

Toriel was disapproving of Asgore's methods, and often scolded him for his treatment of their son. She made sure to show Asriel all the love she could to make up for his father's treatment. She and Asriel were extremely close, and she kept Asriel's kind side from fading and encouraged him to be his real self, at least in private.

**Chara**

Unlike Chara's canon counterpart, Underfell Chara was raised by a father that loved them, though their mother left when they were very young, unable to cope with raising a child with health problems. They were a sickly child with damaged lungs and an immune disorder and were not expected to live long, but their father was determined to give them the best life possible. He worked hard from home to pay for their medical care and spent a lot of time with them when he could, homeschooling them, reading to them when they couldn't get up from their bed, and playing with them whenever they had the energy. He was a kind, accepting man and Chara learned to be the same. They fought their illness with determination, stubbornness, good humor, and kindness. They were determined to live life to the fullest and ended up living long past what their doctors had thought.

Unfortunately, their father developed cancer when Chara was fourteen, and died after a year of fighting the disease. Chara's mother could not be located and their relatives did not want to take in a sick child who would need a lot of expensive medical care, so they were going to be taken into the foster system. But Chara ran away before this could happen, grieving over their father and afraid to go into foster care. They ran up to Mt. Ebott to hide, but when running into a cave to get out of the rain, tripped over a root and fell into the Underground.

**Chara And Asriel**

Like in canon, Asriel found Chara when they fell. Being concerned for the fallen child but still wanting to act tough, Asriel grumbled about helping them and even called them weak, but still took them home, where Toriel, still being her loving self, took care of Chara's wounds. When Asgore saw Chara, he was angry, but Toriel forcefully insisted that they take the child in, telling Asgore that she would NOT let him take his revenge on a sick child that had nothing to do with his parents' death. Asgore, who still loved Toriel deeply and still retained a shred of his former self, gave in, though he avoided Chara for a while.

Asriel acted tough and even like a jerk around Chara at first, but Chara didn't fall for his act, knowing it was just that, an act and saying right to his face, hands on their hips, "Azzy, I'm not falling for that. Whether you admit it or not, I know you're a nice guy. You would have just let me rot out there if you weren't." Asriel was secretly impressed by this kid who was a head shorter than him telling him off, and the two grew close, with Asriel eventually acting like his true self to them when they were in private. Chara and Asriel would playfully bicker, play together when Chara was strong enough, and draw together during Chara's bad days. But one of their favorite things to do was to make goofy videos together, and Chara would tease Asriel when he forgot the lens cap.

Unfortunately, Chara's health grew worse as their lungs and immune system weakened further, and soon there were more bad days than good ones. It was soon apparent to Chara that they were dying when they started to cough up blood, though they tried to hide it at first from Asriel, and it became apparent to Asgore and Toriel as well. Toriel grieved, and Asgore secretly did as well, as he had begun to grow fond of the brave, determined little human, but he also talked to Toriel about using Chara's soul after they died to see if it could be used to pass through the barrier so he could get the other six souls they would need to break it.

Chara overheard and was extremely worried. They didn't want their monster family to get hurt or any of their childhood friends from the village, so one day, when Asriel came in to cheer them up by getting them to smile and leaving the lens cap on on purpose, they finally broke down and told him they were dying. They told him what they had heard Asgore say, and knowing Asgore would refuse to listen to them and possibly even Asriel, asked him to be the one to take their soul. They mentioned that they had read in the plaques that human souls lingered after dying, not just after being killed by monsters, and had the idea to either see if they could find people with who could break the barrier from outside, or to only use the souls of people who had already died. They also asked to be laid to rest in the golden flowers in their village, both because that's where they wanted to be buried and because they thought humans would think kindly of Asriel if they knew he had broken free to bury his sibling in the place they had loved so much.

Asriel cried at knowing his best friend would die, but Chara reassured them that they were no longer afraid and that even though their broken body would die, their soul would remain with Asriel forever, which comforted Asriel. Asriel agreed to go through with the plan, wanting his family to be safe and for there to be peace between humans and monsters, and kept a comforting vigil by Chara's side until they died. He then absorbed their soul and tenderly carried his sibling's lifeless body to the surface.

Unfortunately, the plan failed like in canon. The humans attacked upon seeing Asriel carrying Chara's body, not registering that it had no wounds. Chara panicked and tried to fight back, wanting to save Asriel, but Asriel stopped them, saying that the humans were just afraid. Badly wounded, he took Chara's body back to the Underground, and dusted in front of his horrified parents' eyes.

The death of his son made Asgore snap completely, the last shred of good in him leaving. He vowed to have every human who fell murdered and their soul taken, and his new motto became "Kill or be killed." Any monster who objected was killed and monsters were encouraged to gain LV to turn them into an even stronger fighting force. Knowing his son had been killed even though he had absorbed a human soul, Asgore made the choice to wait until seven souls had been gained so he would be able to obliterate the humans with the power of a god by use of the souls after breaking the barrier.

**Toriel**

Upon hearing the declaration and seeing the madness in the eyes of who once had been her beloved "Gorey," Toriel took Chara's body and fled to the ruins, vowing to protect any human who fell, much like she did in canon.

Six humans fell before Frisk. All six left, and word traveled back of the violent ways in which each child had died. With every death of a child she had loved, Toriel's sanity slipped more.

The first three, Felicity, Violet, and Benji, the souls of Patience, Integrity, and Kindness, would remember the loving Toriel of canon who took care of them.

David, the soul of Bravery, would remember someone who had tried to care for them, but who suffered bouts of depression or hysteria.

Justin, the soul of Justice, would remember a barely stable woman who would call him by the wrong names and would go between caring and angry at odd intervals, and who had almost attacked him when he tried to leave.

And poor Andrea, the soul of Perserverance, would remember the woman who had cared for her, but suffered bouts of violence and insanity, and who had attacked her when she tried to escape, leaving her badly wounded, and not surviving long outside, her injuries making it hard for her to defend herself.

When Flowey escaped Alphys and arrived at the Ruins after his first Reset(his first death at the hands of his own father, who had not believed he was Asriel and been enraged at Flowey's claims that he was, and he had burned Flowey to death slowly), he would find his mother's mind completely gone, and she would either break down or attack whenever he tried to tell her he was Asriel. Reset after reset after reset, he tried, but could never bring her back to herself. Finally, after dying several times, he gave up hope.

When Frisk fell, she found this Toriel as well, and a grieving Flowey telling her quietly that she had once been the most loving mother ever, but that the mother she was was gone. Frisk would spare Toriel due to the fact that she was still Flowey's mother, but she never would want to live with Toriel again.

**Flowey**

Flowey is much different from his canon counterpart, and this is caused by one reason.

When Alphys created him, a fragment of Asriel's soul remained on the flower she used, giving Flowey the ability to feel emotions as fully as he could when Asriel, something Flowey sometimes wished he didn't have in this kill or be killed world.

Alphys performed various and painful experiments on Flowey, "her living, sentient vessel," testing what he could and couldn't do, seeing him more as a test subject than a living being. Flowey managed to escape her and tried first to go to Asgore, but Asgore was enraged by Flowey claiming to be Asriel and killed him. Flowey discovered his reset abilities, waking up in the garden again. When he escaped Alphys for the second time, he looked for his mother, but when he found her in the ruins, he discovered only an insane shell of who she once was. No matter what he tried, he couldn't bring her back to herself, and after many resets, attempts, and even a few deaths, was forced to give up and reset again for the final time. He started over, and being as unoriginal with names as his father, took on the name Flowey The Flower. He traveled through the Underground, learning how to save and load and avoiding powerful monsters as best he could. At times he would gain EXP, but his soul fragment nagged at him, making him feel terrible, and he LOADED over it. He eventually made his home in the ruins where monsters were weaker, and stayed away from as many people as possible. He didn't try to make friends, though he felt lonely, not wanting to show any weakness, knowing it would get him killed. His life was miserable and filled with danger until a human named Frisk fell, a teenage girl he felt an immediate connection to, both lost souls in a dangerous world. Their friendship would begin with an act of kindness, and grow into an unbreakable connection.

**Frisk**

Underfell Frisk was born Francesca Johnson, but was nicknamed Frisk by her parents when she was a toddler due to her habit of trying to steal cookies from the cookie jar in creative ways when she thought no one was looking. The nickname stuck, and almost everyone referred to her as Frisk after that, from her parents to her teachers. She was a very loved and cheerful little girl who loved "helping" her parents cook, playing outside, drawing, and being read to.

But tragedy struck when she was seven. Her parents' car was hit by a drunk driver on the way home from a New Year's party, killing them both and orphaning Frisk. With no relatives willing to care for her, she was taken to an orphanage. Most of the staff there were kind to her, but the grieving child refused to believe her parents were gone and refused to see any families who thought about adopting her as well as lashing out or throwing tantrums at times, saying they were going to come back and pick her up. Eventually, with counselling, she did accept that her parents were gone, though she still struggled emotionally with the fact.

Frisk had trouble making friends due to the fact that many of the other children were either being adopted or moved into foster care, or like her, were struggling with their own demons and didn't show much interest in making friends. Permanence was something she did not have in the orphanage.

When she was ten, she was sent to her first foster home, but only stayed there seven months. Frisk could be distant or clingy depending on the day and her emotional state, and she had problems and occasional fights at school, and they struggled to figure out how to relate to her. When her foster mother realized she was pregnant, the couple decided that they might not have the time or the money to raise both their own child and Frisk and sent Frisk back to the orphanage. Frisk tried not to show it but she was heartbroken by the rejection.

In the orphanage, she did finally find a bright spot in her first friend, a fifteen year old boy named Adam. He had left a dysfunctional family and was a tough guy and a loner, or at least acted like it to keep from getting hurt again. One night, Frisk couldn't sleep and snuck outside the orphanage for fresh air, where Adam was sitting on the step, smoking a cigarette and painting the grassy hills near the orphanage under a starry sky. At first he told her to go away, but she retorted that she had the right to sit on the step too and plopped down next to him, even asking him questions about the painting as she was bored and lonely. He rolled his eyes, but gave one or two word answers to her questions. He told her he'd beat her up if she told anyone that he was smoking or doing anything as "soft" as painting. Of course he never did, and she never told either. He made her feel a little less lonely even with his gruffness and she kept coming out at night to talk to him, and though he at first told her she was annoying, he eventually started really talking to her as he enjoyed the company of the "little brat" as well. He became a sort of big brother figure to her and was rather protective in his own way. He was the guy who would pick a fight with a boy twice his size and beat the crap out of him, but he was also the type that would secretly take care of a bluebird with a broken wing. He was the type to steal from random people, but could also create the most beautiful drawings. He always carried a knife, but what no one else knew was that he used it to create wood carvings and would only ever use it in a real emergency. He even taught Frisk how and when to use a knife, unknowingly teaching her a skill that would help her survive the Underground a few years later. When Adam was eighteen and Frisk was thirteen, he enlisted in the army. The night before he left, he gave Frisk a knife he had very carefully painted for her to remember him by, one side with a jagged red and black pattern to represent the side he showed strangers, and the other side upon which was carefully painted a beautiful sunset, representing the side only the people he trusted fully could see. In return, Frisk gave him a drawing she had spent months perfecting of the bluebird he had taken care of. She clung to him before he left and he hugged back awkwardly and promised he would return. He sent her letters at least once a week while in the army.

When Frisk was fourteen, she was placed with another foster family, her foster parents being Daniel and Mikeala Williams. Daniel had been in a motorcycle accident which left him in a wheelchair, so he worked from home and Mikeala was a veterinarian. The two were unable to conceive children so they decided to foster and wanted to give a home to an older child as teenagers were less likely to be adopted. They saw Frisk's case file and she felt right to them.

Frisk was polite but rather distant at first, not wanting to let them into her heart and get hurt again, but they lavished her with love, as did their pets; Daniel's German Shepard service dog Adrian, Lady Godiva the hyper, always loving brown pit mix, and Puff the "evil" siamese who would rub up against people, then nip.

Frisk loved animals and Mikeala was able to connect with her through that, sometimes bringing her foster daughter to help at the vet's office, which Frisk enjoyed. Daniel spent a lot of time with her as well, helping her with her homework and cooking with her. Slowly Frisk began to open her heart to them though she did remain slightly cautious.

On the anniversary of her parents' death when she was fifteen, Frisk, wanting to be alone for a bit to think about her parents and also worrying because Adam's regular letters had suddenly stopped and she feared for his safety, took a walk, carrying her sketchpad with her. She hiked to Mt. Ebott, wanting to sit up there, watch the sky, think of her parents and Adam, and draw, but ended up falling into the Underground where she met Flowey.

Two paths are open to Frisk now, Neutral and Pacifist. But whichever way she decides, she'll have the help of Flowey and a ghost kid named Chara.

**Chara(During The Events Of The Game)**

Underfell Chara's ghost returned to awareness whenever the first child fell, but was unable to make any form of contact with anyone. No one could see or hear them.

They followed the child. They saw with horror that the underground had gotten worse, monsters fighting, piles of dust in the streets, the little eight year old girl they were following being attacked and brutally beaten. They tried to cry out for the madness to stop. But no one heard them.

Nobody came.

Chara could only watch as the little girl was dragged to Asgore. Could only watch as Asgore brutally murdered the child.

And the same happened for the next five. Chara could do nothing to save them.

Chara grieved. And they were angry. They especially hated Asgore for what he had done, and also blamed themselves for getting Asriel into the mess that had gotten him killed.

They traveled the Underground as a wandering spirit. They saw what monsters had become. They saw Toriel lose her mind and both grieved for and pitied her.

And then when wandering through Hotland, they saw Alphys injecting determination into a dusty yellow flower. Watched as slowly a face began to form. And shocked when it opened its eyes and spoke in Asriel's voice. They Checked him and could see a fragment of Asriel's soul.

They cried with joy. They tried to speak to Asriel, but like the others, he could not hear them. Still they stayed close to their brother through deaths and resets. But no matter what was done to him, Flowey somehow retained the heart of their beloved Asriel, and this gave them hope.

Though they no longer cared about the other monsters, they wanted their Azzy to get out safe.

And then Frisk fell.

Chara watched with joy and relief when Frisk treated Flowey with kindness and the two became friends.

And they were very relieved when they spoke and Frisk turned to listen.

As long as Frisk didn't hurt Flowey, Chara didn't care which path they chose. Their soft voice would lead Frisk through the Underground and they watch over their brother and new friend, wanting only the best for them.

**Sans And Papyrus**

In public, Sans and Papyrus will act like they hate each other, yelling or even coming to blows.

But that is not the true Sans and Papyrus, only an act to keep other monsters from using them against in each other.

In truth, Sans and Papyrus are as close as brothers can be. When inside their home with the door locked and windows shuttered, the two would act more like canon Sans and Papyrus, showing each other affection, treating each other's wounds, bantering together and snuggling on the couch.

Sans retains the same love of puns as his Undertale counterpart, but in public, they have an aggressive or violent undertone if he feels threatened. He too has multiple jobs to take in more money, and still retains his laziness, but he's much lighter of a sleeper. Often if he hears a monster coming, he will pretend to be asleep and if they try to attack him, they always get a nasty surprise of sharpened bones and a Gaster Blaster.

He often calls Papyrus "Boss" in public and usually do whatever Papyrus orders, and Papyrus lets it be known publicially that Sans has some use to him.

He still does share puns with Toriel, but they aren't as close as in canon. Toriel will get him to promise to give Frisk a painless death if necessary, not wanting "her child" to be brutally murdered by Asgore.

Besides the joy buzzer, Sans will delay trying to kill Frisk until Frisk and Flowey reach the judgement hall. At this point, he won't want to do it unless Frisk was to kill Papyrus, but he feels it's more merciful than Frisk being murdered by Asgore. If Frisk is pacifist and she and Papyrus have become friends, he will keep his brother from knowing what he's doing, not wanting to hurt him.

Papyrus is much less friendly and optimistic in public, though he retains his loud voice and grandiose behavior. He actually has lower LV than most people think, but he will beat a monster who attacks him or Sans to the point of 1 HP and then just walk away, saying that the monster is too pathetic to be worth killing. In truth, he does not want to gain too much LV as he once lost control and attacked Sans after gaining a level of LV dusting a monster trying to kill them.

Sans is more honest with Papyrus here and had made sure to train him, so Undyne took him seriously when he trained for the Royal Guard. In private, Undyne and Papyrus developed a friendship as Papyrus went through training, though they kept it well hidden.

Papyrus's puzzles are more deadly than in canon, and he will try to kill Frisk to get her soul to give to Asgore so the barrier can be broken and he can be free to go to the surface with his brother.

However, if Frisk says and does the right things, she can get through to him and befriend him.

**Undyne**

Undyne was an orphan who Asgore began training many years after Asriel and Chara died as he saw high potential in her. She seemed to thrive under the harsh training methods and quickly rose to become Captain of the Royal Guard.

She is somewhat harsher than her Undertale counterpart, but does retain things like her love of explosive cooking and her love for Alphys.

She still remains the only monster that can manufacture their own Determination, and will fight just as hard against death as her canon counterpart.

She will not make any speeches before her fight, instead attacking Frisk violently. Her pattern is more difficult than canon Undyne, though she still can be defeated by Frisk outrunning her into Hotland. She will still let Frisk go if Frisk pours water on her.

**Alphys**

Alphys hides all her true shyness under a "mad scientist" exterior, always talking about the cruel experiments she does to prove her power. She is not the most physically strong monster, but is still a formidable opponent, using deadly puzzles, lasers, and traps rather than directly confronting someone in a physical fight.

At Asgore's orders, Alphys experimented with the bodies and souls of some of the fallen children and discovered Determination was what made the souls stronger. She took the bodies of monsters that had fallen down and used them to test the effects of Determination on monsters, which created the Amalgamates. Unlike canon though, Alphys was forced to show her results to Asgore, who was impressed, and ordered her to continue the Determination experiments to turn monsters that would otherwise be dead into super soldiers. He also will send some live monsters who committed treason or other crimes to Alphys to be used as live test subjects, which strikes fear into the hearts of many monsters. Only Undyne is unafraid of Alphys.

Though Alphys acts like she enjoys the cruel experiments, they take a toll on her and sometimes she abuses painkillers in an attempt to cope.

Undyne and Alphys met in a similar way to their canon counterparts, with Alphys standing at the top of a waterfall. Undyne realized what she was about to do and angrily forced her away from there. The two first argued, then began actually talking. A friendship began to grow between them, though kept well hidden, and slowly grew into more. The two began dating before the events of the game, though this is kept secret from anyone else, including Mettaton.

**Mettaton**

Alphys and Mettaton are not friends like they are in canon. In fact, Mettaton is terrified of Alphys, and for good reason.

Mettaton is more gentle than most monsters, and in fact even secretly started a human fanclub from feeling a connection to them after viewing various forms of human media. Mettaton retained his desire of being a star, and wanted to leave the violent Underground with his cousin to live in peace on the surface, who he was at that point extremely close to.

Unfortunately, Mettaton was ratted out for being a human sympathizer. Knowing he was going to be taken in and not wanting Napstablook to try to save him and get killed, he wrote a note which read, "Sorry, Blooky. My dreams wait for no one." wanting Napstablook to think he left on his own so they wouldn't risk themselves looking for him.

It worked too well, and Napstablook felt betrayed and did not attempt to find him. Thry became angry and secluded themselves from everyone.

Mettaton's punishment was that he was sent to Alphys to become a test subject, and Alphys forced him into a robotic body she had built to act as both her security guard and a weapon.

Mettaton still has his shows as Alphys saw his talent in performing and knew it could make money to upgrade him and pay for her other inventions. He does not enjoy it though as his shows are highly censored of anything that made humans look good and he is often forced into fights or on occasion to shoe torture and death on his show. Any mistakes he makes are punished heavily.

When Frisk arrives, Mettaton tries to delay harming her for as long as he can, feeling sympathy for the young human girl and the flowef she protects. Frisk will see that he's one of the few kind ones and try to save him along with Flowey in both Neutral and Pacifist.

**Author's Note:**

> If you have any ideas for anything you want to see in the series, let me know!


End file.
